Composite supporting structure



, 1930 3 SheetsSheet l Filed OCT. 1'7

INVENTOR V/'c'for F//mmel BY 63W t D a""/ ATTORNEYS Feb. 23, 1932. A v.F, HAMMEL 1,846,682

COMPOSITE SUPPORTING STRUCTURE Filed Oct. 1.7, 1930 B SheeS-Sheet 2 if zATTORNEYS Feb. 23, 1932. v F HAMMEL 1,846,682

COMPOSITE SUPPORTING STRUCTURE Filed Oct. 17, 1930 3 Sheets-Sheet 5ATTORNEYS Patented Feb. 23, 1932 PATENT OFFICE VICTOR F. HAMMEL, OF NEWYORK, N. Y.

COMPOSITE SUPPORTING STRUCTURE Application filed October 17, 1930.

systems or of telephone and telegraph lines and the like.

An object of the invention is to provide a composite supportingstructure bf the above type having a lower section of metal, preferablyiron or steel, and an upper section of wood.

A further object is to provide an electrically welded latticed or wovenmetal pole for use in said composite structure which combines theelements of maximum strength in bending, in torsion and in columnaraction consistent with lightness in weight and facility and economy ofconstruction* A feature of the latticed pole constructed in accordancewith this invention is that when implanted directly in the ground forvertical support thereby it adords maximum resistance against earthmovements as compared to existing poles when similarly supported.

The composite supporting structure of this invention is adapted toprovide the most economical support for overhead electric power, lightand communication conductors and cables, as well as grounding wires.

This application is a continuation in part of my copending applicationSerial No. 310,889, filed oct. 6,1928.

A composite supporting structure of the type specified when utilized asa. support for overhead power or communication lines possesses manyunique advantages as compared to the commonly used pole structuresconsisting entirely of metal such as steel or entirely of Wood.

The all-steel pole in addition to being more expensive than thecomposite structure is necessarily more massive and heavy than the steelportion of the composite structure and hence is more diicult totransport to the many wild, mountainous and otherwise inaccessibleregions where the poles are frequently required.

The all-wood pole is not always available in the lengths required forpole line construc- Serial No. 489,455.

tion. Unless especially treated, as by creosoting, it is quicklyattacked by vermin such as boring insects which enter the wood at ornear the ground, the resultant decay soon causing collapse of thestructure. Brush fires frequently destroy miles of wood pole line, whilelightning in its transit to earth often shatters a wood pole.

The composite structure obviously overcomes the above objectionablefeatures inherent in the all-metal or all-wood pole. The metal lowerportion protects the pole against destruction by fire or attack byvermin. The metal portion, being relatively light as compared to theall-steel pole may be easily transported to the regions where requiredand where almost any local timber supply will prove adequate to completethe structure.

A pole having its upper section of wood of definitely establishedlongitudinal dimension together with a metal lower section gives greatprotection against destruction by lightning, lVith a definite gapbetween the steel section and the conductors the lightning will readilyjump from the conductors across the wood and seek ground through thesteel without burning the conductors or shattering the wood.

Since the top wood section in the composite structure is so much smallerthan the timber required for an entire wood pile, a great amount ofreasonably cheap timber not heretofore satisfactory will become usefulfor pole line construction. In many foreign countries and in someregions of the United States this factor is of prime importance sincequantities of short slender timber constitute the only available localsupply. Likewise, other woods having characteristic propertics moresuitable from the electrical point of view, but previously unavailablebecause of the acceleration of decay when in contact with the earth willbecome applicable.

"he latticed or woven steel pole which is preferred for the lowersection of the composite structure comprises rods wound in left andright hand intersecting helices having substantially equal pitch,together with flanged longitudinal bars of angle section eX- tcnding inalignment with the intersections of th-e rods and electrically weldedthereto at such intersections. The angle bars are positioned outside ofthe helically wound rods with their vertices pointing outwardly. Oneadvantage of this particular construction is that with the poleimplanted directly in the ground for purposes of support, greatresistance is obtained against ground movement of the implanted portion.Thus any transversely applied force such as that dueto wind pressurewill in tending to shift the pole sideways, cause the earth to pack orwedge more tightly between adjacent angle inembers thereby automaticallyincreasing the resistance to movement in proportion to theapplied force.

In the drawings:

Fig. l shows a composite pole or column in accordance with thisinvention comprising a latticed steel lower section and a wood uppersection;

Fig. 2 shows an H frame comprising two composite poles in accordancewith Fig. l trussed together by cross member supporting high tensionpower lines; the wood poles being utilized to cari', ground wires as aprotection against lightning. n

Figs. 3, 4 and 5 disclose the structural details of the latticed metalpole of the Fig. l composite structure. Fig. 3 is a side elevation ofthe metal pole supported directly in the ground. Fig. 4 is a sectionalview along the line 4 4 of Fig. 5; while Fig. 5 is an enlargedperspective view ofa portion of th-e structure.

Fig. 6 is a graphical disclosure of the man-- ner in which the pole ofFig. 3 is resistive of ground movements of the implanted portion due totransverselyT applied forces.

Referring to l, there is shown a columnar structure comprisng a steellower section A of electrically welded latticed construction, the lowerend whereof is implanted directly in the earth at B for supporting thestructure in a vertical position. Inserted in the upper end of the steelpole A is a wooden pole or post C to the upper end of which are attachedthe cross-arms D having affixed thereto pins and insulators E forsupporting the conductors F of an electrical transmission system, theconductors being preferably supported on the wood pole C over man-heightfrom the metal section A, as indicated by the proportionate dimensionsof the cross arms D and the length of the wood pole C, Fig. l. An aerialcable G is shown below the cross-arms, its supporting steel cable I-Ibeing ailixed directly to pole C.

The wood top section provides an excellent construction of highelectrical resistance for insulating a ground wire from the conductors.To this end the cross-arms D and aerial cable G may be attached at thetop `original setting by the simple operation of attaching a wood top ofany required length for future additional conductors as developmentrequires. To this end a wood top of given length may readily be replacedby a longer one without interruption to service. Due to the inherent sagin conductors F between poles, this change can easily be accomplished byloosening the connecting means between the steel section A and the woodtop C, raising the wood top, holding it to one side and inserting a newwood top section. This flexibility of construction further provides astructure easily adjustable inV height to suit the topography by using astandard length of steel base and varying length of wood upper section.

The latticed steel pole A is constructed as set forth in my copendingapplication above referred to and comprises, as shown more clearly inFigs. 3 to 5 inclusive, rods l, preferably square or circular incross-section, wound in left and right hand tapering helices of eoualpitch, together with trussed or flanged longitudinal bars 2,specifically of angle section, extending in alignment with theintersections of rods 2, being electrically welded thereto at thecontact points 3 (see Fig. 4) adjacent the intersections.

It can be demonstrated that a pole constructed in this manner is ofstrength greater than a tubular pole of the same external dimensions andcontaining the same material, and thus constitutes a great improvementover such poles in that it achieves the same objectives at a markedsaving in material and reduction in dead weight.

The latticed pole of Figs. 3 to 5 inclusive is ideally braced againstevery sort of bending, twisting or compressive force and is thus strongwhen acting as a beam or as a column or when subject to torsionalstresses. l

The latticed construction reduces the resistance to windpressure whilethe cylindrical configuration renders the pole of equal strengtn forforces applied thereto from any transverse direction. By distributingall of the metal a maximum distance from the axis of the pole, a largesection 'modulus is attained whereby the structure operates with maximumelliciency when acting as a beam or as a column.

The flanged longitudinal members have inherent stii'nessagainst bendingand being bound together by helical rods which follow the naturallyoccurring lines of compressive stress in a solid or tubular polesustaining a load, render the pole of maximum strength as a colunm.

By extending the helical members in accordance with both right and lefthand spirals a set of tension members are provided to take up the loadunder torsion regardless of the direction of twist. Thus the torsionalstrength is increased since the rods 1 are able to withstand withoutfailure much greater loads under tension than under compression.

By electrically welding the longitudinal and helical members at thepoints of contact, the strength of the pole is not only increased ascompared to the employment of riveted or clamped joints, but theconstruction thereof may be accomplished with much greater facil ity andeconomy. lVhere bolted joints are employed the necessity for punchingand aligning the rivets holes, and inserting and capping the rivets isinherently a slower and more expensive procedure than electric welding.

The specific construction for the latticed pole disclosed hereinprovides great resistance against shifting or movement of the pole w enimplanted directly in the ground for purposes of support. This actionwill be understood by referring to Fig. 6.

It a transverse force is applied in the direction F1 it obviousl causesthe earth to become more densely pacged or wedged between the angles A1to A5 inclusive and this automatically increases the resistance of thepole against movement in proportion to the magnitude of the appliedforce. In any movement of the structure in the earth there is a circularshell of earth 5 which moves in conjunction with the pole, causing aresistive action by virtue of the greater frictional resistance betweenthe shell 5 of earth and the surrounding earth. I the material includedwithin the annulus 5 were composed entirely of steel or wood, the polewould out thru the earth much more readily than with the constructionshown, because the coefiicient of friction between earth and wood, orbetween earth and steel is considerably less than that between earth andearth.

In addition to the resistance against earth movement thus provided bythe present structure, attention need only be called to the great savingresulting from being able to set the pole directly in the groundomitting the usual concrete base.

It is of course not essential that the helically wound rods 1 of thelatticed pole be continuously curved thereby producing a circularconfiguration when viewed in elevation as shown in Fig. 4. It sometimesbecomes of advantage to have the rods 1 follow straight line pathsbetween adjacent angle bars 2 such as to produce a pole of polygonalshape when viewed in elevation.

The modification of Fig. 2 comprises an H frame consisting of a pair ofcomposite poles N, each similar to that of Fig. 1, trussed together bymeans of a cross member K to which are affixed insulators L supportinghigh tension lines M. The wood tops of poles N carry ground wires Pwhich serve to protect the system from lightning. The structure may besuitably braced by means of guys R.

An adaptation in accordance with Fig. 2 may of course be applied to theusual forms p il' framed steel transmission towers and the I claim:

1. A pole or column for supporting overhead electrical transmissionlines and the like comprising, a metal lower section adapted to be setdirectly in earth, and a wood pole upper section of the order ofone-third to onehalf the length of said entire pole, and electricalconductors insulatedly supported upon said wood pole over man-heightfrom said metal section.

2. A pole or column for supporting overhead electrical transmissionlines and the like comprising, a latticed metal lower section adapted tobe set directly in earth, consisting of flanged longitudinal barsintegrated by diagonal latticing rods coextensive with said bars, and awood pole upper section inserted in said metal section, said wood polebeing of the order of one-third to one-half the length of said entirepole, and electrical conductors supported on the latter and located inthe upper half thereof.

In testimony whereof I afiiX my si nature.

VICTOR F. HAM EL.

IOC

